The invention discloses a machine vision-based tire tread detection method and provides a machine vision-based tire tread detection method. According to the technical scheme of the invention, based on the machine vision software halcon technology and the image processing algorithm, the system reliability and the measurement accuracy are ensured, and the production efficiency and the product quality are improved. In this way, the intelligent tire tread detection is realized and the urgent demand of social production is met. According to the method, a tire tread image is photographed by an industrial camera, and then a to-be-processed region of the image is extracted based on grayscale distribution characteristics after being subjected to smooth filtering and threshold segmentation. After that, the pre-preprocessed image is subjected to feature selection, so that the length of the tire tread can be recognized. The lower line segment of the tire tread is extracted by using an edge detection operator, and the included angle thereof relative to a horizontal line segment, namely the tilt angle thereof, can be figured out. The mapping relation between the coordinates of the image and the length thereof is calibrated, and then the actual length of the tire tread can be calculated. The method is fast in detection speed and high in precision.

Machine vision-based tire tread detection method

The invention provides a detection method for surface shapes of multiple surfaces of a transmission component and relates to the technical field of measurement. The detection method comprises the steps of: on the premise of measuring a wave aberration of a to-be-detected component by use of a reverse hartmann light path detection device, adding multiple groups of different surface shape errors tothe surface shape of each surface of the to-be-detected component in a light ray tracing model by use of a modeled detection system established by a computer to obtain the corresponding wave aberration; solving a minimum difference value between the wave aberration and an actually measured wave aberration in the modeled detection system; and finally obtaining an actual surface shape error of the to-be-detected transmission component. With the detection method for the surface shapes of multiple surfaces of the transmission component, the technical problems in the prior art that detection for multiple surfaces of the transmission component does not possess high precision and universality. The invention has the beneficial effect that the detection method with high precision and large dynamicrange is provided for detection of the surface shapes of multiple surfaces of the transmission component.

Detection method for surface shape of multiple surfaces of transmission component

The invention provides a free-form surface detecting method based on reverse Hartmann detection and relates to the technical field of measurement. Structure position parameters of an optical path system are calibrated; an ideal optical path system model using a detected object as an ideal surface is established; according to the ideal optical path system model, an experiment is performed to obtainwave front aberrations including surface errors and structure errors; parameters of the ideal optical path system model are adjusted to conduct two-step structure error correction based on high-orderand low-order aberration separation and optimization is conducted on the detected data to obtain a standard optical path system model; ray tracing is conducted on the standard optical path system model, wave front aberrations caused by surface errors of the detected surface are detected, and the surface errors of the detected surface are calculated. The technical problem is solved that in the prior art, high-precision free-form surface detection does not have universality. The free-form surface detecting method has the advantages that two-step optimization based on Zernike fitting is conducted on structure errors, structure position errors of the system are effectively eliminated, the detection precision of the system is improved, and detection is universalized.

Free-form surface detecting method based on reverse Hartmann detection

The invention discloses a cone beam CT system geometric parameter calibration method. The method includes the following steps that projection data of a calibration model at a projection angle is collected; the center line equation of each linear object is determined according to the projection data of the model, the position of the intersection point of center lines is worked out, and then the lengths of the sides of a quadrangle formed by projections of the four linear objects on a detector are worked out; phi is calculated with the ratio of the left side to the right side, theta is calculated with the ratio of the upper side to the lower side, and delta D can be worked out according to the length of any side of the projection quadrangle; eta, delta u and delta v are calculated with phi, theta and the projection coordinates of the intersection point of two adjacent straight lines on a calibration template on a detector plane which includes phi and theta and deviates by delta D in the X axis direction; after the geometric parameters are obtained, FDK reconstruction with the parameters is carried out, and a corrected reconstructed image is obtained. According to the method, improvement is carried out on the basis of a four-point model, the wireframe model is proposed, and the model retains the advantages of the four-point model that 6 geometric parameters are worked out through one time of projection and the calculation amount is small, and improves noise immunity compared with a point model.

Cone beam CT system geometric parameter calibration model and method

The invention discloses a defect detection method based on transmission structured light, and is used for detecting the defects of a detected object with high transmissivity. The method comprises thefollowing steps that: firstly, generating stripe structured light, projecting the stripe structured light to the surface of the detected object, and after the stripe structured light is transmitted through the detected object, generating deformed stripe structured light; collecting the deformed stripe structured light, and utilizing a modulation degree technology to convert a collected light intensity graph into a modulation degree graph; and combining with a subsequent algorithm to obtain the surface defect information of the detected object. The method is especially suitable for the defect detection of a large-size large-curvature glass cover plate. Compared with a reflection system, a transmission system which is put forward by the invention eliminates the influence of parasitic stripes, improves the stripe contrast ratio of a collected image, improves the signal-to-noise ratio of an original image and improves a measurement result. In a whole detection process, a complex calibration process is not required, the height information of the object does not need to be subjected to integral reconstruction, errors brought by an integral algorithm are avoided, and the method has the characteristics of being quick, easy in operation, simple and practical.

Defect detection method based on transmission structured light

The invention provides a high-numerical-aperture optical fiber point diffraction interference device used for three-coordinate measurement and a method thereof, and relates to optical measurement. Light emitted by a laser device is divided into transmission light and reflected light via a polarized beam splitting prism. Point diffraction spherical wave front W2 is generated at a sub-wavelength aperture optical fiber emergent end by transmission light, and point diffraction spherical wave front W1 is generated at the sub-wavelength aperture optical fiber emergent end by reflected light after being reflected by a moving reflecting mirror. A CCD detector acquires W1 and W2 interference fringes, and three-dimensional coordinate measurement of a measured object is realized via multi-step phase-shifting and a double iteration algorithm of an L-M algorithm. A problem in the prior art that high-numerical-aperture and high-energy diffraction spherical wave front is difficult to realize simultaneously by a point diffraction interferometer used for three-coordinate measurement is solved. The beneficial effects are that probes of two sub-wavelength aperture optical fibers act as measuring probe heads, the high-brightness and high-numerical-aperture point diffraction spherical wave front is acquired, the requirement of light sensitivity is reduced and measurement range of an optical fiber point diffraction interference system used for three-coordinate measurement is enlarged.

High-numerical-aperture optical fiber point diffraction interference device used for three-coordinate measurement and method thereof

The invention discloses a free-form surface detection method which includes the following steps: using three-coordinate measuring equipment to measure and calibrate the structural position parameter Sof a reverse Hartmann test optical path including a to-be-detected reflective spherical surface, a projection screen and a CCD camera; determining surface shape error data W0 of the to-be-detected reflective spherical surface according to the measured and calibrated structural position parameter S; determining the surface shape deviation optimization objective of the to-be-detected reflective spherical surface through Zernike fitting according to the measured and calibrated structural position parameter S and the surface shape error data W0; and determining the deviations of the initial measured and calibrated structural position parameter S according to the determined surface shape deviation optimization objective, and determining the actual surface shape error Delta(W) of the to-be-detected reflective spherical surface according to the deviations. By using the method, the surface shape measurement error of the free-form surface is reduced.

Free-form surface detection method and system

The invention provides a high-precision large-dynamic range measurement system and a measurement method for transmission element aberration, which relate to the technical field of measurement A three-coordinate measuring machine is used for pre-calibrating structural position parameters of the measurement system, a to-be-measured transmission element is placed between a display screen and a CCD camera, a four-step phase-measuring method is adopted to solve phase distribution corresponding to stripes, the actual spot coordinate value of a point on the transmission surface of the to-be-measuredtransmission element corresponding to the phase projected on the CCD camera is obtained, a ray tracing method is then used to generate an ideal coordinate value based on structural position parameters of a detection optical path, slope error calculation is carried out on the to-be-measured transmission element on the basis, and finally, an integral method is used to obtain element aberration data The technical problems of small dynamic range and expensive equipment for non-contact high-precision transmission element surface detection in the prior art can be solved, a universal feasible method is provided for large-dynamic range transmission element aberration measurement, and an extremely important practical application value is realized

Kong Ming

Papers

High-numerical-aperture optical fiber point diffraction interference device used for three-coordinate measurement and method thereof

Free-form surface detection method and system

Detection method for surface shape of multiple surfaces of transmission component

Free-form surface detecting method based on reverse Hartmann detection

High-precision large-dynamic range measurement system and measurement method for transmission element aberration